package net.hnspi.util;

import java.awt.Color;

import java.awt.Font;

import java.awt.Graphics;

import java.awt.image.BufferedImage;

import java.io.ByteArrayInputStream;

import java.io.ByteArrayOutputStream;

import java.util.Random;

import javax.imageio.ImageIO;

import javax.imageio.stream.ImageOutputStream;

public class RandomNumUtil {  

    private ByteArrayInputStream image;//图像  

    private String str;//验证码  

    //验证码序列。

    private static final char[] randomSequence = new char[] { 

     '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b',

  'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'm', 'n', 'p',

  'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', 'A', 'B',

  'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N',

  'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z' };

      

   private RandomNumUtil(){  

        init();//初始化属性  

    }  

     

    public static RandomNumUtil Instance(){  

        return new RandomNumUtil();  

   }  

     

    public ByteArrayInputStream getImage(){  

       return this.image;  

   }  

     

    public String getString(){  

        return this.str;  

    }  

      

    private void init() {  

        //       在内存中创建图象  

        int width=85, height=20;  

        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);  

        //       获取图形上下文  

        Graphics g = image.getGraphics();  

        //      生成随机类  

        Random random = new Random();  

        //       设定背景色  

        g.setColor(getRandColor(200,250));  

        g.fillRect(0, 0, width, height);

      //创建字体，字体的大小应该根据图片的高度来定。

        Font font = new Font("Times New Roman", Font.PLAIN, height-2);

        //设置字体。

        g.setFont(font);

        //随机产生155条干扰线，使图象中的认证码不易被其它程序探测到  

        g.setColor(getRandColor(160,200));  

        for (int i=0;i<155;i++)  

        {  

         int x = random.nextInt(width);  

         int y = random.nextInt(height);  

                int xl = random.nextInt(12);  

                int yl = random.nextInt(12);  

         g.drawLine(x,y,x+xl,y+yl);  

        }  

        //       取随机产生的认证码(6位数字)  

        String sRand="";  

        for (int i=0;i<6;i++){  

          int index = random.nextInt(35);

             String rand = String.valueOf(randomSequence[index]);

            sRand =rand;  

            // 将认证码显示到图象中  

            g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt(110)));  

            //      调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成  

            g.drawString(rand,13*i+6,16);  

        }  

        this.str=sRand; 

        //       图象生效  

        g.dispose();  

        ByteArrayInputStream input=null;  

        ByteArrayOutputStream output = new ByteArrayOutputStream();  

        try{  

            ImageOutputStream imageOut = ImageIO.createImageOutputStream(output);  

            ImageIO.write(image, "JPEG", imageOut);  

            imageOut.close();  

            input = new ByteArrayInputStream(output.toByteArray());  

        }catch(Exception e){  

            System.out.println("验证码图片产生出现错误："+e.toString());  

        }  

          

        this.image=input; 

    }  

     

    private Color getRandColor(int fc,int bc){  

        Random random = new Random();  

        if(fc>255) fc=255;  

        if(bc>255) bc=255;  

        int r=fc+random.nextInt(bc-fc);  

        int g=fc+random.nextInt(bc-fc);  

        int b=fc+random.nextInt(bc-fc);  

        return new Color(r,g,b);  

   }  

 

}